The present invention relates generally to operations performed and equipment utilized in conjunction with a subterranean well and, in an embodiment described herein, more particularly provides methods and apparatus for interconnecting well tool assemblies in continuous tubing strings.
Continuous tubing strings, such as coiled tubing strings, have been used for many years in wells. However, one problem with continuous tubing strings is how to interconnect well tool assemblies in the tubing strings.
If a well tool assembly is to be interconnected in a continuous tubing string then, of course, the tubing string must be severed and connections must be made between the tool assembly and the tubing at each end of the tool assembly. With present methods and apparatus, this operation may require many hours to perform.
Continuous tubing strings having lines embedded in their sidewalls have recently become available for use in wells. An example is FIBERSPAR composite coiled tubing available from Fiberspar Spoolable Products, Inc. of Houston, Tex. The FIBERSPAR composite coiled tubing is a composite coiled tubing with eight conductors embedded in its sidewall. Making a connection between this tubing and a tool assembly at a wellsite, where the tubing is severed (i.e., there is no preexisting connector attached to the tubing), typically takes approximately 12 hours to accomplish.
One solution that has been proposed is to interconnect well tool assemblies in the tubing string, and then spool the well tool assemblies on a reel along with the tubing. The reel is then delivered to the wellsite with the tool assemblies already interconnected therein, and the tubing string may be conveyed into the well, without having to make connections at the wellsite. One problem with this approach is that the well tool assemblies may have an outer diameter greater than that of the tubing, in which case spooling the tool assemblies on the reel with the tubing may cause damaging stresses to be imparted to the tubing, and special injector heads are needed to convey the large diameter tool assemblies into the well. Another problem is that many tool assemblies, such as well screens and packers, may be too long and inflexible to be spooled onto the reel.
Therefore, it may be seen that there exists a need for improved methods and apparatus for interconnecting well tool assemblies in continuous tubing strings.
In carrying out the principles of the present invention, in accordance with embodiments thereof, methods and apparatus are provided which solve the above problems in the art. In one embodiment, a method is provided which permits well tool assemblies to be rapidly interconnected in a continuous tubing string at a wellsite.
In one aspect of the invention, a method is provided in which tool connectors are attached to a tubing string at respective predetermined downhole locations for tool assemblies. The tubing string is wrapped onto a reel with the attached connectors. The tubing string is then deployed into a well from the reel. As the tubing string is deployed, the tool assemblies are connected to the respective connectors.
In another aspect of the invention, a method is provided which permits a line extending through a tubing string to be extended through a tool assembly interconnected into the tubing string. Connectors are used which both connect the line at each end of the tool assembly and structurally attach the tool assembly to the tubing. Such connectors are also used to connect between portions of the tubing.
In a further aspect of the invention, a connector system is provided. A connector of the system includes a gripping structure for grippingly engaging the tubing string, an internal seal structure for sealingly engaging an interior of the tubing string and an external seal structure for sealingly engaging an exterior of the tubing string. Where the tubing string has a line extending therethrough, the connector includes a line connector attached to the line in the tubing string.
In a still further aspect of the invention, a sensor apparatus is provided. The sensor apparatus includes sensors embedded in a sidewall material of a tubular body of the apparatus. The sensors are connected to one or more lines also embedded in the sidewall material.
These and other features, advantages, benefits and objects of the present invention will become apparent to one of ordinary skill in the art upon careful consideration of the detailed description of representative embodiments of the invention hereinbelow and the accompanying drawings.